Dear Martine,
Make sure you are passing the right values to the parameters. It should work fine i guess.
Hope you have written code something like this.
IF eo_message IS NOT BOUND.
CALL METHOD /bobf/cl_frw_factory=>get_message
RECEIVING
eo_message = eo_message.
ENDIF.
CALL METHOD eo_message->add_message
EXPORTING
is_msg = ls_msg
iv_node = is_ctx-node_key
iv_key = lr_root->key.
ls_key-key = lr_root->key.
APPEND ls_key TO et_failed_key.
Thanks,
Bharath.